Transition trainer



Sept. 13, 1949. G. H. HOLLINGSWORTH ET AL 2,481,510

TRANSITION TRAINER Filed Dec. 28, 1945 6 Sheets-Sheet l Sept. 13, 1949.

G. H. HOLLINGSWORTH ETAL.

TRANS ITION TRAINER.

Filed Dec. 28, 1945 6 Sheets-Sheet 2 minima Sept. 13, 1949. G. H HOLLINGSWORTH ETAL TRANSITION TRAINER 6 Shets-Sheet 3 Filed Dec. 28, 1945 M m e \\\0M W 5 W E Y@ 3 W W w f @E Z M M i HIDE wil--.

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TRANSITION TRAINER l Filed Dec. 28, 1 945 6 Sheets-Sheet 4 lSept. 13, 1949. G. H. HOLLINGSWORTH ETAL A 2,481,510

TRANSITION TRAINER Filed Dec. 28. 1945 6 sheds-sheet 5 aff ,4free/verl /sw//fffe y WW J M W. f A Vapo w wmf Z a $5 w. MTM l .3, gf f C Z Fd M@ Z e W M W j 4 Sept. 13, 1949.

Filed Dec.

/fjf Pny/P Patented Sept. 13, 1949 UN ITED STAT E S PATENT OFFICE TRANSITION TRAINER George H. Hollingsworth, Long Beach, Calif., Ernest V. Burton, Seymour Johnson Field, N. C., and Rocco A. Traficante, Meriden, Colm.

Application December 28, 1945, Serial NiLi'iWw'JGi)l (Gi-antes under the act of March 3, 1,883', as amended April 30, 1928; 370 O. G. 757) 7 Claims.

The invention described herein may be manufactured .and used by or `for the Government for governmental purposes, without the payment to Aus of :any royalty thereon.

This invention relates to a device for the transition training of pilots to enable pilots who have completed training on primary training aircraft to become thoroughly familiar with cockpit and flight procedure and the handling of pursuit and multiengine aircraft prior to attempting any iiights in the latter.

During the :recent war a large number of accidents have occurred in the transition training of students, particularly where students are required to fly high performance single-engine pursuit airplanes. This :difficulty has been largely traced to the fact that heretofore the student was instructed in the position of lthe Various power plant and other instruments and controls in the airplane cockpit and became familiar with the cockpit layout only by being seated in the airplane and by study .of instruction manuals and briefing. This course of transition training did not provide for the actual operation of the power plant controls for the sequence Yof operation during takeoff, flight and landing, nor did it provide for instructing the student such that he would instinctively take the proper measures for safety in an emergency. As -a result of the above type of training Anumerous accidents have occurred during the .early flight period on pursuit aircraft because the student became confused when faced with a multiplicity of instruments and controls and failed to carry out the proper operation procedure, examples .being failure to lower the flaps in landing, failure to retract the undercarriage after take-off and -failure to operate the fuel system such as to vcui; in a full tank upon exhaustion of a mainor auxiliary tank.

In accordance with the present invention a trainer -is provided comprising a full-sized aircraft mounted vabove the -ground in a cradle support such tha-t the engine and propeller may be operated exactly as during the take-off, flight and landing phases of an actual flight and the undercarriag-e and wing flaps may be extended and retracted to simulate the actuation of the same during periods of take-off and landing. The aircraft engine, in .addition to driving the propeller, is used in the conventional manner as a source of power for 4actuationof the hydraulic system for landing gear and flap .actuation and the aircraft in all respects is similar -to a .service machine. An instructors booth is located away from, and slightly -to the rear of., theA aircraft wing so that the instructor alwayslihas the aircraft ,and cockpit in full `view iandtheai-rcraft is provided with the usual instrument panel .con-taining. the various .engine 'and' flight factorindicators and controls. In the .instructor.s :booth there is provided a master lcontro'lpanel andan instrument panel lduplicating .the :one in `the aircraft. All of the various pressure transmittingsources for deriving :a pressure or an.electrical quantity indication varying as a function .of some .flight operation factor; for example, oil pressure, hydraulic system pressure, .oil temperature,- =.q.uantity .of fuel and the like, .are :directly transmitted from the various transmitter units-'of conventional character in rthe air-planedirectly -to .master instru-ments on .the control panel. The master instruments Aon the ,control panel indicate at all ztimes the actual values of, for enorm-ple,V oil pres-sure, fuel pressure, hydraulicA system pressure and engine manifold pressure and :alsoouantities such as gallons -of fuel remaining .in the respective aircraft fuel tanks,ygenerator amperes, engine revolutions :and :the ,1i-ke, the-control .panel also having indicators indicatingthe fuel tanks selected for fuel suppl-y Aand thepropeller pitchsetting. The duplicate air-craft instrument panels have :the instruments thereon :corresponding to `:the instruments xon lthe master control ypanel connected in parallel to the master :control vpanel with control means provided .so that v.certain:indications such as hydraulic .system pressure,- oil pressure, fuel pressure, manifoldpressure .and the like transmitted to the duplicate .instrument board in the airplane cockpit rand instructors .booth may be altered from the actualsystemcondition to there- .by .simulate emergency operating conditions which require the immediate attention .of the student pilot occupant of rthe trainer.

The'ftrainer oockpitand instructors booth are provided Lwith an .interecommunication system whereby the student and instructor may ,converse in a manner .similar to radio-,conversation with acon-trol tower.

Duringl .operation the student ,is first briefed on a simulated vflight Jof` :a predetermined :duration and after receiving his instructions he climbsinto the .airplane .and is secured in the 3 serves whether the power plant operating conditions are suitable for take-off. The student then opens the throttle and controls the propeller pitch during a simulated take-olf and again adjusts the throttle and propeller pitch for climb and ultimately simulates leveling off at an altitude as indicated on his altimeter which, to-V-jgether with the air-speed indicator, are underY periodofg Vfor example,v i'lfteenminutes the student may prepare for landing and so advise the instructor, who then by watching the instrujments determine whether cockpit procedure and A flap operation and lowering of the undercarriage Vwith respect Vtol indicated air-speed and altitudes is carried out .correctly Yduring the simulated glide, Vapproach and landing.

It is the principal object of the invention to provide grounded ltraining apparatus in which 1an actual Vaircraft power plant, variable pitch propeller, retractible landing gear and wing flapsmay be operated exactly as in a simulated take-off, flight and landingand in which an instructor at all times is aware of the actual operating conditions andemay at will simulate a failure or malfunction of the components to check' the students reaction; I

It is a further object Yof the invention to provide a groundedrtransition training device for instruction in the proper operation of the power plant, propulsion system, alighting gear and flapsof an airplane and in which a full size operative aircraft is cradled to Venable power operation of its components in a manner simulating the actual operation during take-off, fiight and landing, the grounded vaircraft being positioned in full view ofan instructor'positioned externally of the aircraft, instrument and indication means being providedgat the'instructors position for directly indicating the instant value of power plant -and flight operation factors and including means whereby the instructor may give instrument indications in the cockpit of the airplane, simulating indications of malfunction of operative components or dangerous simulated flight factors.

The above and other objects and features of invention will become apparent by reference to the detailed description hereinafter given and to the appended drawings, in which Fig. 1 is an isometric view illustrating the general arrangement of the component parts of a trainer in accordance with the invention; e

Fig. 2 is a side elevation of the aircraftuin Fig. 3 and 3a diagrammatically illustrate the Y oil cooling arrangement found necessary to give Vadequate cooling;

' the cockpit indications of certain of the instruments;

sure indicating system;

Fig. 9 illustrates the hookup ofthe engine intake manifold pressure indicating system;

Fig. 10 illustrates means for obtaining an instrument suction and altimeter indication;

Fig. 11 illustrates the means for obtaining a i simulated air-speed indication;

Fig. l2 illustrates the ammeter circuit and means for controlling the ammeter indication on the instrument panel of the airplane.

Fig. 13 illustrates the fuel quantity indicating system and means for altering the indicated quantity of fuel in the auxiliary or main tanks orboth;`V

Fig. 14 is a schematic illustration of the system;

Fig. 15 is a sectional elevation of a pressure fuel Vresponsive cut-olf valve employed in the sysprise an airplane generally indicated by the reference numeral I, ithe'type shown being a P-47N or Thunderbolt fighter Yaircraft having a fuselage 2, wings 3", retractible undercarriage 4, tail assem- Ybly 5, propeller B and enginevL-housed within the cowling 3', all exactly the same as in aircraft used for flight operation.V The aircraft fuselage 2 is supported adjacent its forward end by'means of a mainconcrete pier I0 sunk in the ground and which is provided withV adjustable jack screws II which are secured at their upper ends to the fuselage structure by riveted attachment means,V

not shown. Concrete piers I2 spaced outboard from the plane of symmetry of the aircraft have ,their Yupper ends contoured such as to form a cradlesupporting the wings 3, and concrete piers I3 are placed adjacent Ythe rear of the fuselage to support the latter by means of a rod I4 passing through the fuselage and suitably secured thereto by means of rivets or bolts, not showin The aircraft I is thus cradledby the s upportingstructure at a height above the' ground sufficient to provide ample propeller clearance as well as clearance for operation of the retractible undercarriage 4.V

By reference to'Figs. 3 and 4 the oil cooling system is seen to includeethev usual pair of oil coolers I5 positioned within the engine cowling, each lhaving serially connected thereto by means of conduits I6 supplemental-oil coolers I8'rigidly mounted on the cen-trai pier IIJ so as to be exposed to the propeller blast'to supply the necessary supplemental cooling. Return conduits 20 Y f cooler hookup and need not befurther described.

Referring again to Figl andas alsoV seen in Fig- 2, the aircraft I is seen -to Vhave the usualV V'instrument boardf22--mounted in the cockpit thereof and which has the various power plant ayisasio and flight factor. instruments mounted thereon, which in the` conventional aircraft are actuated from master sources of" pressure or electric current derived either directly from thesource of pressure or currentA or transmittedtothe instrument board from Vtransmittery unitsall of -which are oldl and well knownin the art. Inaccordance with the.` present invention,A how-even.,A all of the principal functions. to be indicated are transmitted' by means ofL conduits and; electrical conductors generally indicatedby reference numeral 23j to a master. instrument. or* controli panel` 25 from which in turn an instructors and observing trainees instrument panel 214' andthe instrument panel 22v in the aircraftcockpit are respectively actuated.

The controlpanel 25' andi instrument panel 24 are positioned in air'instructors booth 28- positioned outboard'. and slightly toV the rear of the left wing panel'of the airplane so that` the undercarriage, wing flaps, tail` assembly' and cockpit closure are all visible to the instructor through suitable windowsprovided in thecontrol booth.

As seen in Fig. 2reference numerals 2B and 21', respectively, generally indicate the control booth and cockpit units ora conventional telephone inter-communication system which is employed to simulate radio. communication between vthe aircraft andthecQntrOltOWer.. In the present case the instructor serves as .thevcontrol ofcer.

The control panel and instrument panel arrangementiin the\instructors\.booth=.is illustrated in Fig. 4. As seen inv this-.figure fluid. pressure conduits and electrical, conductors lead from the transmitting points,in,the airplane to the master controlppanel 2.5and other uidpressure conduits and electricalconductors lead totheairplane instrumentpanel 22,(Eigs..1land12). inthe airplane and tothe duplicate instrumentpanel, 24 inthe instructors booth. Theconduitsand conductors are generallyindicated byreferencecharacter 23. The conduits 230,-. to 23drespectively transmit fluid pressures, to master. gauge-units 30, V40, 50 andv 653, the` indicated. pressures. being. respectively a measure of hydrauliosystem pressure, engine lubricating oil pressurefuel pressure and engine intake manifold pressure. Conduits 33, 43, E53-and @3.conductvthe indicatedpressures to correspondinggauge units 34,443, 54 and-B4 on the instrument. panel24 and to. duplicate instruments on the cockpit instrument panel..

The controlpanel 25 .contains manually actuated valve units 32311, 42,.41, 52,51; and62, 61 forV isolating.thetransmittedhydraulic oil, fuel and manifold pressures from the... corresponding gauge units on the instrument panels 24 and 22 and to alter'l the indicationiof! these factors on the instruments of the .panels 24 and 22.

Revolution countersv or` tachometers I9 are provided on vthe mastercontrolpanel 25g and on the duplicate.instrumentpanels/Ziand 22. The master control panel 25E also contains almaster ammeter 86', masterfuel quantity-indicator Idd, simulated altimeter; andi air-'speed controls E3 and 84, instrument ammeter-'controlxlk fuel cock selector signal means Hte-|18 and propeller pitch control and indicatingmeanslll-I 55and miscellaneous electric power system switches;

The instrument"boardfinaddition to-the previously noted instruments ir'icludesvr an altimeter air-speed'indicator 80; ammeter 8-'I,` suction indicatorV 16 and'gfuelquantity'gage H12-which are operatively connectedtoinstrument' indication control means on master control i panel 25 andv to corresponding duplicate" instrumentsv on the airplane instrument board In addition the instrument boards22.` and.24f.containa complete set of flight factor instruments which are employed for visual physiological eife'cts.l and' are not operative. The principal-valueofthefinstruL ment panel 2t in the instructors boothfislt'olpermit other trainees to. check: on-Y thecorrectnessLof operatingtechnique of the trainee'l pilot operating the trainer. Thev manner in which the various instrument indications. are modiedf as desired bly the instructor andy transmitted: to the student will now be described.

In accordance with the present invention one of the important features is the fact that the actual pressure or electricalquantity which may be a measure of either a power plant' or flight factor function such as oil pressure, hydraulic system pressure, or the like is transmitted'inits actual value to the control panel and fromthe control panel may at the instructors selection be transmitted unchanged to the duplicate in'- strument boards positioned respectively in` the control booth and in the airplanecockpit', but means are provided interposed between-v the master indicating units and the duplicat'eindicators whereby the instructor at Will-may alteror falsify the indication of the latter'without affecting the true value of thefunctionsuchasengine oil pressure. This provisionV permits` simulated engine oil pressure, hydraulici system pressure, fuel pressure, or engine manifoldlpressure failure to be simulated without actually. disturbing the system on the airplane such as to cause actual failure or dangerous operationofthe powerfpla'nt or other instrumentalities. Y

The general schemeof thisfeatureof'ltlie invention is illustrated schematicallyin Eig; 5. in which point P1 is a source of'pressureto be indicated, for example, engine oilpressur'e', hydraulic system pressure and thelike, which is conducted by means of a conduit P2 vto a master gauge Grpositioned on the master control panel25 A; first control or isolating valve V1. is provided. invthe conduit P2 and this conduit isy branchedA into conduits P3 and P4 which leadrespectively to `the cockpit gauge unit G2mounted onthe instrument panel 22 of the airplane l.l of. Fig. 1 and-arcorresponding duplicate gauge unit Gs mountedon the duplicate instrumentpanelfuin theinstructors booth. The conduit .P2 vis-furthertappedbetween the valve V1 and the conduits P3 and Pri-for a return conduit P5 which may,.for example, returnfluid to a reservoir, suchras anoiltank.y or the like, or may be venteddirectly, tothevatmosphere, the conduit P5 having the controlY or bleeder valve V2 mountedthereiniand adjustable by the instructor. In the operation ofthis system whenvalve V1 is open and"bleedvalve;V2,-is closed the true pressure transmittedfrom the source through conduit P is indicated. on gauges.Gi,.-G2 and G3. When the instructor desires to; give a false indication, indicative of for exampleV a falling or reduced oil pressure, he firstclses Valve V1 while the system is in normal operation so that whatever Value of pressure then Aexists. in conduit P2 willbe trapped in conduits P4 andPs. This action isolates gaugesGz and G3 fromthe master gauge G1 and by then slightly opening the bleed valve V2, the trapped' fluidunder pressure in conduits P4 andPa is bled'tothe. return conduit P5 causing a slow drop. the pressure indications ofgauges G2 andiG. Bleed valve V2 is closed Whenever the. desired/.low pressure indicationv is .given on gauges G2 ,andjGa At'any time Valve V2 is closed'ivalve Vi may be opened to cause gauges G2 and G3 to read the vtrue pressure Vas indicated at all times on gauge G1.. By momentary sequential operation of .valves V1 and V2 the pressure indication in the vairplane cockpit may be caused to fluctuate or the indication of a falling or reduced pressure may be given in the manner described abovewithout aiecting the true pressure in conduit P2 or its true indication on gauge G1. In general, the system is employed. throughout the various pressure function indicators which will now be described separately. w

Hydraulic System Pressure Indication seen in Fig. 6, the system Yfor indicating hydraulic fluid pressure is similar to that of Fig. 5 Vand in which' the pump 28, conventionally driven by the engine, receives fluid from reservoir 29 and delivers same under high pressure at the pump outlet whichY is connected by means of a conduit 23a to a master hydraulic pressure gauge 3U mounted on the master control panel 25, Fig. 1. The gauge line 23a is connected by means of a conduit 3l and isolatingvalve 32 to parallel conduits 33 which are respectively connected to duplicate hydraulic pressure'gauges 34 and 35 positioned respectively upon the instrument panel 24 in the control booth and on the 4instrument panel 22 mounted on the aircraft. A

return line 36 and control valve 31 positioned therein serve under manual manipulation to control the bleed-off of trapped pressure back to the reservoir; and, hence, at the instructors wish control the actual indication on the gauge units 34 and 35 after the gauge units have been isolated from the general system by actuation of valve 32 in the same manner as in the operation of the general pressure indicatingsystem described in conjunction with Fig. 5.

Oil Pressure Indication The oil pressure indication system illustrated in Fig.: '7 is similar in general to that of Figs. 5 and 6 and in which an oil supply tank 38vsupplies oil to the engine drivenrpump, not shown, the pressure supply of which is led, by means of conduit 23h, to the master gauge 40 mounted on control panel 25 and thence through conduit 4l and isolating valve 42 to the duplicate indicating gauge lines 43 to the gauges 44 and 45 respectively mounted on instrument boards 24 and 22. Re-k turn line 46 and bleed control valve 41 function in the same manner for altering the cockpitoil pressure indication as the return and bleed control valve V2 discussed in the system of Fig. 5.

Fuel pressure indication The fuel pressure indication system as illustrated in Fig. 8 is generally similar to the system of Fig. 5 and in which a main or auxiliary tank 48 serves to supply fuel to an engine driven pump 49 which in turn supplies fuel under. pressure to the engine carburetor, and a conduit 23e transmits fuel pressure directly to the master fuel pressure gauge 50 mounted on the master 'control panel 25 in the instructors booth. The fuel pressure may also be transmitted by means of a conduit 5l through an isolating valve 52 to conduits. 53 which respectively connect to fuel pressure gauges 54 and 55 mounted respectively on the auxiliary instrument panel 24 in the instructors booth and on the instrument panel 22 in the airplane cockpit. Return line 56 and bleed control valve 51 function in the same manner as the return system, Fig. 5, Vtl'iat is, by opening valvep52 .and closing valve 51, gauges 50, 54 and 557Will all read the actual fuel pressure, While by closing valve 52 and opening bleed Valve 51 the fuelpressure indication on gauges 5 4 and 55 may be low- Yered to indicate incipient engine failure, requiring the student in the airplane to switch fuel tanks to restore aLV fuel supply to the engine.

Manifold pressure indicating system vThe manifold pressure indicating system illus.-

ftrated in Fig. 9 is also identical tothe Vgeneral system of Fig. 5 inWhich a conduit 24d transmits Ypressure from the intake manifold of engine 1 directly to a master gauge 66 on the control panel 25,-conduit 6|,isolating valve 62 when open, and conduit 63 transmits manifold pressure to mani- Yfold pressure gauges 64 and 65 mounted respec- ,tively on instrument panel 24 in the instructors y,booth and on instrument panel 22 in the airplane.

A return conduit 66 vented to the atmosphere by means of a bleed valve ,61 may be manually actuated by the instructor.rv In this system opening isolating valve 62 and closing valve 61 causes the same gauge indication on allr of the manifold pressure gauges While closing valve 62 and opening valve E1 vents the trapped pressure gradually to the atmosphere and-causes manifold pressure indication to fall in the vsaine manner as de- Y. scribed with reference to Fig 5. This, of course,

Warns the student of incipient power plant failure or improper operation., Y

Altitude simulating means The lrneans for indicating altitude of the simulatedtrainer flight is illustrated in Fig. 10 and comprises a conduit 1| connected to a motordriven suction pump,Y not shown, positioned in vthe instructors booth and having a branch 1|a connected to the static pressure connections of conventional altimeters 15 and 15a positioned respectively .on the instructors instrument board 24 and on the duplicate instrument board 22 in the cockpit of the airplane so that by varying the suction in the instrument cases varying altitude Vmay be indicated., Conventional suction gauges 16 and 16a mounted on the respective instrument boards 24'and 22 also indicatev the instrument suction pressure and a needle control vent valve 11, having a manually actuated control needle assembly 18 vents the line 1l to atmosphere to regulate the altituderindication, on the respective altimeters 15 and 15a to correspond to the assumed altitude obtained at various stages of the simulated flight. By means of the control valve assembly a simulated rate of ascent and descent Vmay be obtained.

ir speed indicating system' The means for indicating thesimulatnedsair Y speed of the training Yairplane during the simulated ight as illustrated in Fig. 1l comprises a pressure pump 19 positioned in the instructors booth 28 and driven by an electric motor, not

Y shown. The air pressure output of the pump 19 is l tive .mainand auxiliary fuel tanks.

onrinstrument panel -24 of the instructors booth and on the instrument panel 22 in the cockpit of 'the airplane. yits simulated ight commences the instructor may gradually close off the bleed port 83 Ito-cause.agradual increase'inpressure in conduit 8| corresponding to the vincrease in air speed during the period -oi take-off and adjust the sameduring the period of climb and cruise and similarly readjust'the-'same during the simulated landing approach so that the air speed-isproperly correlated to the engine R. P. M. and other factors andcan at'any'time indicate lan approaching stall.

Ammeter indicating system The means for indicating the current in the aircraft electrical system is illustrated in Fig. 12 and comprises a conventional ammeter shunt 85 vwhich shunts the yindicating system around the main bus bar and having a rmaster vainmeter 35 directly connected across the shunt 85 so that at all times itindicates 'theactual current flow in 'the aircraft electrical system. Two similar ammeters, one |51 mcuntedon the instrument board 24 in Ythe instructors booth and the other B8 mounted ontheinstrumentboard 22 in the cockpit, are connected in parallel in such a fashion by means of a double-pole, doubleethrow switch 89 so that with the switch, as shown in the figure, ammeters', 81, `and 88 1will-all read identically. wIn order however, to vary the :indicated ammeter reading in the .airplane cockpit the switch 89 may be thrownto the upper position, in which case the ammeters 81 and IB8 will be connected in series from the bus barto the ground 'return side of the electrical system through a iixed resistance 90 and variable resistanceSL the adjustment of the latter which will vary the ammeter reading as desired without yaffecting vthe reading on master ammeter`85. A-signal'light92.indicates when the switch .89 .is `rrroved 'to 1the variable :indicating position. Thissystem, .apart from being electrical, furnishes thesame control over indications as is provided in the general -fluid pressure system illus- .trated in Figandpermits the'instructor to vary :the ammeter indication in the airplane cockpit `so as to cause asimul'ated'indication ofa pending lfailure of the relectrical .system Yor malfunctioning of the same.

Fuel quantity indicating system -quantity indicators (not shown) so as'to indicate at all times .the actualfuel'quantity in the respec- Parallel connected .electrical indicating units |02 and |04, identical to the master indicator |00, are respectively mounted on the .instrument vpanels and 22 respectively located in the instructors booth and airplane cockpit.

Main tank and auxiliary tank float actuated transmitters in the form of potentiometers |06 4and |01 are-directly electrically connected to the respective main `and auxiliary tank indicating units of the master indicator |00. Double-pole, double-throw switches |08 and |09 have their lswitch blades"respectivelyfconnected to the main and auxilarytankindicating'units (not shown) of the indicators |02 .and |04. When the switches |08 and |09 are positioned as lshown in Fig. 13 the main and auxiliary tank indicating -units of the duplicate fuel .quantityindicators |02 .and |04 are electrically connected in vparallel with the corresponding units-of master indicator |00. In this condition indicators |00, |02andf|0|| Willread the true value of fuel quantityin the main and auxiliary fuel tanks as ydeterminedby the control of iioat actuated potentiometers |06 and |01.

Ii the double-pole, vdouble-throw switch |09 is thrown to its other positionthe auxiliary tank indicating units of indicators |02 and |04 will be connected to a -manuallyvactuated contr-ol potentiometer positioned 4on theV master control panel 25 in the instructors booth. :By manipulation of potentiometer |l0the auxiliary fuel quantity indication on indicators |02 and |04 may be varied at will without disturbing the true indication on master in'dicatorfl00.. Similarly if switch -i is thrown to its'other position the-maintank indicating units of indicators |02 and 104 yare electrically connected to acontrol potentiometer H2 which can be manipulated -to cause any desired main tank fuel yquantity t'o beindicated on the corresponding units of indicators |02 and |04 without disturbing the true indication of main tank fuelquantity on-masterfindicator |00. The potentiometer ||2 like the potentiometer ||0`is positioned on the master-control panel 25. The Ainstructor at any time ymay thereby falsify the fuel quantity 'indication `of either the vimain or auxiliary tank vgiven yto `the student in the 'airplane cockpit vwithout varying the truefuel yquantity read on master gauge |00.

Fuel system The fuel system employed in thetrainer is generally :indicated in Fig. 14 in which reference numeral |20 indicates, for example, the auxiliary fuel tank having .an 'electric rriotor driven Vpump generally indicated 'as '|2:| and lenergized from a power source suchas aibattery'l 22, which may be 'cut onor oi by meansfo apontrol switch `|23at the instructors option. Fuel delivered by the pump |2| passes throughanautomatic valve |24 to a manually actuated selector `cock 35'and :from 'thence to the engine-'driven :fuel .pump 49. As seen in Fig. 15,'the valve `|24 comprises a main valve body v|25 having an Iirilet .port |26 and la discharge port |21. Flow'from 'the inlet `to the discharge `port is adapted 'to `vbe controlled by a flexible diaphragm |28 which whenseated forms ra shut-off valve'to'blockany flow of v'fuel from the inlet to the discharge port. `The vavediaphragm |23 is `provided with Va metalbacking rdisc |29, which is acted on vlby'a loa-dingspring |30 that is normally set to close the valve .port/|21 if theinlet 'pressure drops below threepoundsilper square inch. A valve stem |3| and 4,guide diaphragm f|32 serves to complete the assembly. This ldevice is operative such that whenthe spump 42| is disabled by opening switch |23 of Fig. lltlietinlet'uel pressure at port |26 is finsu'liicien't to hold the diaphragm |28 in'its `upperposition and it Ais urged downwardly by spring 5|.30to the dotted line position as indicated 'cutting off any iiow of fuel from port |26 tooutletport 121. VThis automatic 'valve is necessary because itotherwise might be rpossible for fuel to flow vdue to suction from the yengine pump even though 'the auxiliary -pump was disabled.

Fuel passing through the automatic 'valve |24 of Fig. 14 flows to 'the'manually'actuated selector valve or cock |35 whichfinay'be connected leither l l to the maintank orauxiliary tank` supply and from the selector vvcoclifuel'flovvs to the engine Pump $9Y and to the carburetor Vof the engine in the usual manner. Thewiring arrangement for the fuel system is indicated'in Fig. 16 and corn- -prises parallel actuated switch units |40 and I 4| which in turn are actuated in common with the fuel selector valve movable and to three positions; namely, Om Ma'in'tank and Auxiliary tank positions. WhenY in the main position the switches |40 and [4| control the flow of current to energize the fuel tank pump on the main tank V(not shown) while in'fth'e auxiliary position the auxiliary fuel tank pump |2| is` energized. The switch |23 previously desci'ibed'permits the circuit tcj the auxiliary fueltank 'pump tc be disabled and 'afsimilar switch |'23a provides for dis- "ablingfthe main tank booster pump (not shown). Propeller pitch control system 'Ihe'propellerpitch Acontrol systemjas illusy trated in`Fig. Y1'1', is conventional in that the propeller 6 has4V the 'pitch :of-its blades varied by means of an electricvmotor andV gear reduction unit r6a and is fed with current through slip rings 6b as in the Curtiss electrical variable pitch propeller,Y whichsystemisV 'provided with the usual selector switch'unit'l50 'mounted in the cockpit vof the 'airplane 'on the' instrument panel 22 and whicnswitch can be' placed in an automatic p0- sition whereby an engin driven governor, not shown, isadaptedto` automatically control the pitch^ of the propeller" to'maintain a preselected R. P. M.` Whileiri either the increase or decrease position the automatic control is cut out and the pitch may be increased .or decreased from the existing setting to a desiredvalue Within predetermined limits." Thissystem is provided with fthreeindicator lights '|5|,|52`and' |53 mounted on the' master control panel 25 in the instructors booth which indicate'whether the propeller is in the automatic'or increase or decrease pitch positions. This systeinis purely conventional and the only variation thereof to adapt'the same lto use in the trainer'is the provision' of an additional three-position switch' |55 similar to switch and positioned'on-'the master control panel 25. The switch permits the instructor at any time to take over control'of the pitch of the propeller and adjust the same even though the stuf dent has the propellerV pitchfadjustment switch |50 in automatic position. By moving this switch to the increase position the automatic system is cut out and the instructor may increase the pitch to* reduce. engineR. PJM. and similarly by` moving the switch to the decrease position he may decrease the pitch to'increase the engine R. P. M. Operation of the switch |55 by the instructor is for the purpose of causing the engine R. P. M. to speed up or decrease, indicating pos- -sible failure of the automatic pitch control mechanism which reduiresxthe student to manually control the' pitchV ofthe vpropeller to again obtain .the desired R. P. M. setting. Signal lights |5|, |52 and |53 at all times give complete in-'i -formation to the instructor, when'coupled with the R; P. M. reading, as to what the incident pitch condition of the propeller might be.

Fig.`,18 illustrates signalv light or indicating ysystems employed to-adviseY the instructor of the Y operation status of various electrical circuits such as the ignition, battery, and generator and indicating thefuel selector cock position.

In Fig. 18 at a the `magneto switch generally indicated at |l has a signal light |62 and circuit I2 therefore arranged such that thelight is illuminated when the magneto switch is in the -*Left, Right or Both position but is extinguished when the switch is in the Oil position.

Fig. 18 at b illustrates a main battery circuit in which switch |65 is the main battery switch leading to the output conductor or bus bar |56 and having a high resistance signal lamp |68 shunted between the bus |66 and the return side of the system such that the signal lamp is illuminated when theV main switch |65 is closed.

In Fig. 18 at c one side of a double-pole, double-throw switch |10 is utilized to close an indicator circuit through signal lamp |15 while the other side of theV switch is used toV close the main generator'circuit; Y e Y Fig. 118, at d indicates Ythe circuit of Fig.. 16 employedy for operatingthe fuel pumps on the fuel tanks and actuated in conjunction with the selector cock |35 as previously explained and further showing signal lamps |16, |11 and |18y connected from the live side to the grounded or return sides of the electrical system and roperative respectively to indicate the Oif Main tank and Auxiliary tank positions of the fuell selector cock.

, Y General operation In operation, the student, after entering the cockpit of the airplane, starts the engine in the usual manner and calls to the instructor over the inter-communication system 26-21 (Fig. 2) for taxi-out instructions and take-olf and the instructor calls his instructions back over the intercommunication set using tower procedure. After the pilot theoretically approaches the takeolf spot he runs up his engine in accordance with brieng instructions and goes through the proper procedureof a magneto check, propeller check, controls and instrument check. Observations are made by the instructor on his technique and brief notes are kept as material for criticism after the simulated flight. YVA green light in the control booth is then flashed simulating a mobile control unit on the runway, and the trainee advances the throttle to take-olf limits which rare checked by the instructor and trainee in the control booth by observation of the engine tachometer 10 and master manifold pressure gauge 60 (Fig. 4). With the advance of the throttle noted by increasing R. P. M. the instructor gives a steady increase in indication of air` speed by actuation of the control knob 84 of the air speed indicating system of Fig. 11 and at a hundred and ten miles per hour simulated air speed notes whether the trainee has retracted his landing gear, the trainee noting the indication'of hydraulic gauge 35 and landing gear warning light. YAfter the simulated take-oil the instructor by actuating the control knob 18 of Fig. l0 causes vthe simulated altimeter reading to be increased at a rate of approximately 500 feet per minute and it is noted whether or not the student decreased the throttle setting for climb.

After additional altitude has been gained, the instructor increases the air-speed indication to two hundred miles an hour and manifold pressure should have been reduced by the trainee to twenty-live inches for cruising. The traineepilot has been briefed to switch his tank to auxiliary and is then called on for continual check as to instrument readings and their signification. Also, his auxiliary fuel supply may be cut at any time, with the iirst indication being a drop Ain in fuel pressure, instituted by the instructor by closing valve 52 of the fuel pressure indication system, Fig. 8, and gradually opening bleed valve 51 which will cause a drop in the indicated fuel pressure on the gauge 55 in the airplane cockpit. This may be followed by a cutting out of the motor driving current supply for the auxiliary fuel pump |21 of the auxiliary fuel tank i2@ by opening switch l23, Figs. 14 and 16, causing valve |214 of Fig. 15 to close which will gradually-cause an actual drop in fuel pressure and coughing and stoppage of the engine if the fuel selector cock l35, Fig. 14 is not switched to the other source of supply. Besides controlling fuel pressure indications and the fuel supply, Variations can be made in the setting of the ammeter by means of the electrical indicating system of Fig. 12 `and in this connection the propeller may be made to run to high or low R. P. M. at the will of the instructor causing the pilot to use proper corrective action by placing it under manual control and increasing or decreasing the propeller pitch to regain the desired engine R.. P. this procedure being accomplished as described with respect to the propeller pitch control system of Fig. 17. The manifold pressure can also be lfluctuated by `means of the manifold pressure indicating system of Fig. 9 with the result that the trainee should call the instructor over the interphone communication system for an emergency landing after reduction of power. The hydraulic gauge indicating the pressure in the hydraulic system canv always be controlled by means of the indicating system of Fig. 6 so as to result in a zero pressure indication in the cockpit after the pilot simulates break-away and lowers his wheels for landing. In this way it can be determined Whether the trainee pilot actually checks his hydraulic gauge as an additional indication of the. wheels being down. The oil pressure indication in the airplane cockpit can -be reduced at. any time during. flight, by means of oil pressure in.- dicating system of Fig. 7, causing the trainee pilot to ycall the instructor, similar to calling the tower, for an emergency landing and to reduce his power settings.

The pilot, prior to his simulated flight, the inter-phone communication system 26--2'L Fig. 2', being employed in a manner similar to conventional norm-al radio procedure and the pilot calls on his break-away, reduces his throttle setting and lowers his landing gear in an approach for a simulated landing with the instructor correspondingly decreasing the air speed indication to a hundred and fifty miles per hour.

The trainee calls on his base leg and the instructor by increasing or decreasing his air speed by means of the air-speed indicating system of Fig. l1 requires the pilot to make appropriate use of the throttle which can be checked by observation of the tachometer 1li on the master control panel and on the duplicate instrument board in the instructors booth. On his approach, the trainee must lower the flaps when an air speed of a hundred and thirty miles per hour is given him, with the instructor slowly reducing it to one hundred miles per hour by means of the` air speed indicating system, Fig, 1l, at which time the. simulated landing is. assumed to have been completed and the flaps are raised and engine shut olf. vBy means of the trainer system provided by the presen-t invention it is possible to. continue a number of simulated flights ineXactly the same manner as indicated. above without causing any emergency indication to arise and that at any time during the simulated flight-lan emergency such as power plant 'failureor hydraulic system failure or' the like vas cutlined alcove may be indicated to see whether or not the student immediately responds to the indications of 'an emergency situationand takes the proper corrective measures.

'Observationmade of' trainees Whohave-undergone transitionl training on a trainer in accord"- anee with. this invention has shown that if the troubles.- noted were experienced by them while in the yair onen actual'. flight, one, out of seven, who demonstrated confusion in the training de.- vlice, `prolialcly would have experienced the same difculty resulting in a. fatal accident to himself' or his airplane i-nactual flight. While all of the troubles: artificially placed and confronting the traineesv during instruction on a trainer in accordanee with the present invention are not: everyv dayy occurrences, their existence is recognized and this: training devicer therefore, rcan prevent 'a repetition oi such. an occurrence when the pilot has been-checked out in actual flight.

Continued use of' trainers built in accordance'. with the principles `ci the present invention. as

illustrated has conclusivelyl shown that; after four hours instruction and lbriefing. on proper cockpit procedure and simula-ted flight in the trainer, ac.- cidents dueto faulty procedure-irractual night can belargelyprevented.

While this invention has been illustrated and described, vparticularly with respect to a. high performance ghter airplane principles of theinvention are equally well adapted" to.V use in giving transitional instruction on multi-engine. aircraft', since the principles of the invention can be yapp'liedftoplural power plants as readily as toa singie engine. aircraft merely by exten-sion of' the indication system herein generally disclosed and the invention is also applicable to give training: onf large:y 'multi-engine aircraft, such- -as B-29 bombers to members of the crew yother than the .pilot introducing emergency malfunctioning of various components of the aircraft requiring the crewmembers to take emergency vmeasures of a standard procedural form. I

Having described one formof the invention, other alternatives, variations and changesv therewilt become apparent to those skilled in the art as falling within the scope ef the invention as: denect iin the appended claims.

Vlllfeclairn:

1. A transition training device `for instructing astudentV pilot inthe propermanipulation of an aircraft .power propulsion unit, retractible landing gear, wing flaps and the like under simulated take off, 'flight and landing comprising, a captive airplane provided with `an operative engine, an automatic variable pitch propeller driven there- :power actuated retractible landing gear and wing' flaps and a plurality of master transmitting means eachfor4 transmitting to a remote indicator a variable quantity' such as a fluid pres-sure', electric current and' thev like representative of the instant value of an operating condition of an aircraft kelemezrt such las the power plant, landing gear, wing flapsv and the like, said airplane being supported in a cradle structure so as to be immobile andl providing ground clearance. for ope-ration' of :the propeller and landing gear, an instructors station positioned laway from and in full vie-w of' 'the airplane and including a master control panef having master indicating instrument-s thereon each operatively connected to a respective one ofisaid" master transmitting means, duplicate instrument boards having indicating instruments thereon corresponding to the master indicating instruments,4 one of said instrument rboards being positioned in the airplane cockpit and the other board being positioned adjacent the master control panel, operative connections ybetween the instruments on the duplicate instrument boards and the master transmitting means, and means adapted :to be controlled at will by the instructor for isolating the one or more of the instruments on the said duplicate instrument boards from operative connection with the master transmitting means to -vary the indication from the value indicated on the corresponding master indicating instrument.

2. The device as claimed in claim 1, in Iwhich certain of said master transmitting means inlclude Vfluid .pressure conduits operatively connected to pressure sources such as the engine oil lubricating system, carburetor fuel supply, engine manifold, hydraulic power system and the like said conduits being directly connected to respective master indicatinginstruments, a-return conduit connected to each fluid pressure conduit, the corresponding duplicate Ainstruments on said instrument boards being connected inwparallel to the respective return conduits, valve means' in eachvreturn conduit to'prevent flow therethrough to said duplicate instruments and valve means in leach return conduit beyond the connection of the duplicate instruments thereto for relieving trapped fluid under pressure in the return conduit to cause a change'in indication onxthe duplicate instruments to simulate the indication of a dangerous operating condition of a component of the aircraft. Y

f 3. The structure as claimed in claim l, in which certain of said master transmitting sources com- Vprise electrical conductors carrying currents pro-- portional to factors such as total current in Athe :airplane electrical supply system, currents which are a measure of the quantity of fuel in the fuel supply system and the like, said master and duplicate instruments connected to said master transmitting conductors to give identical indications, and Vswitch means for disconnecting the duplicate .instruments from said electrical conductors and for connecting the same to adjust-able sources of current of a different value than thel master sourceswhereby the indication on the duplicate instruments may be varied from the value indicated on the corresponding master in`v dicator. v

4. A transition training device for instructing` a-student in the proper manipulation of engine, Variable pitch propeller, retractible-landing gear wing flaps, fuel system and the like under conditions simulating take-oif, night and landing comprising an operative airplane of the type to which transition is to be made, said airplane being cradled so as torpermit operation of the power plant, propeller retractible landing gear and Wing flaps thereof, a master control panel positioned remote from the airplane torbe observed by an instructor and having master instruments thereon operatively connected for indicating the value of operating factors such as engine speed, oil pressure, manifold pressure, fuel pressure, hydraulic system pressure and the like, an instrument panel in the airplane and having instruments thereon duplicating the master instruments, means interconnecting the duplicate instruments to the master instruments such that the instruments normally indicate the same values of the respective operation factors and Vmeans on the master control panel for isolating one orA more of the airplane instruments from the corresponding master instrument and for varyingV the indication thereon to simulate departure of the corresponding operating factor from a safev operating value.

5. 'Ihe structure as claimed in claim el, inf

which certain of said master instruments are connected by main fluid pressure transmitting conduits to the source of pressure to be indicated, branch conduits connected to 'each respective main conduit, pressure transmitting' connections between each duplicate instrument on the airplane instrument board and a respective branch conduit, a manually actuated valvev in each branch conduit for interrupting transmission of fluid pressure .tothe duplicate instrument and. additional valve means for venting trapped fluid under pressure from any selected branch conduit so as to cause a false indication on the corresponding duplicate instrument without disturbing the indication on the corresponding master instrument.

6. In a trainingde'vice of 'the character described, a master indicating instrument operatively connected by a main conduit'to aY source of uid pressure, which pressure is a direct measure of the actual value of anopera'tion factor' of an aircraft such as manifold, oil, fuel `and rhydraulic system pressures and .the like, a duplicate instrument connected by a branch conduit to the main conduit'such that the master and duplicate instruments normally give the same indication and manually actuated valve means for isolating the duplicate instrument from pressurer transmitting relation with the main conduit and for relieving trapped fluid pressure in the branch conduit so as to give an altered indication on the duplicate instrument.

7. In a trainingdevice of the character described, a master indicating instrument, operatively "electrically connected to a source of current which varies in accordance With theY actual value of an operationfactor of an aircraft'such as fuel quantity, electrical system current 'and the like, a duplicate indicating instrument, separate electrical connections between the master and duplicate instruments whereby parallel indications are normally given on the corresponding master and duplicate instruments, means for electrically'isolating the duplicate instrument from operative connection with the master instrument and means for supplying the duplicate instrument with electric"current so as to alter the indication thereof from the value indicated on the master instrument.

Y GEORGE H. HOLLINGSWORTH. ERNEST V. BURTON.l

ROCCO A. TRAFICANTE.

'REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Great Britain Aug. 1o, 1933 

